The present invention relates to an adjusting mechanism for binoculars, such adjustment operations as focusing adjustment, diopter difference adjustment and the like are carried out by rotational movement of an operating member.
Binoculars, having a pair of right and left telescopic optical systems, optical axes of which are arranged in parallel, are provided with various adjusting mechanisms such as a focusing mechanism, a diopter difference adjusting mechanism, and a magnifying power changing mechanism, if the binoculars is a magnifying-power-changeable type.
The focus adjusting mechanism enables eyepiece lenses of both the right and left telescopic optical systems to simultaneously move in the direction of the optical axes thereof. The diopter difference adjusting mechanism enables one of the eyepiece lenses to move in the direction of the optical axis thereof with respect to the optical axis of the others eyepiece lens. By operating the diopter difference adjusting mechanism, a diopter difference between the right and left eyes of a user are compensated. Focusing operation should be performed by the focusing mechanism after the diopter difference has been compensated for by the diopter difference adjusting mechanism.
In the adjusting mechanisms of the binoculars, as above, an adjusting member rotatably driving the mechanism is disposed between the pair of telescopic optical systems in general use. When an operating member, such as a knob, which is fixedly secured to the adjusting member, is rotated, the adjusting mechanism is driven.
The operating member is exposedly disposed so as to be easily operated.
With aspect to the diopter difference adjusting mechanism, however, once the eyepiece lenses is moved to compensate for the diopter difference of a user, the adjustment is not needed any more providing the same user uses the binoculars. Further, it is clear that there is no need for adjusting the diopter difference during the operation of the binoculars. If the diopter difference adjusting mechanism is driven after the adjustment thereof, another adjusting operation should be performed, which causes the operation of the binoculars to be very troublesome.
Previously, the operating of the diopter difference adjusting member is preferably formed to have an operable configuration, and disposed at an easy-to-operate position for quick operation. On the other hand, currently, in order to prevent the erroneous operation thereof, the operating member should be formed to be inoperable and disposed at a hard-to-operate position.
Even in the focusing mechanism, when an object distance is nearly infinite, or the difference of the objects distances between precedingly observed object and currently observed objects is relatively small, there are cases in which the observation is preferably executed with a fixed focus. Focusing is dependent upon the depth of focus of the optical system or on the adjusting function of the eyes. In such cases, the operating member of the focusing mechanism is required to satisfy two contrary conditions, that is, easy-to-operate and hard-to-operate conditions which are the same as those required in the case of the diopter difference adjusting mechanism.